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Replacement same model tweeters like a major component upgrade

Hi all. So I blew a tweeter last week on my Martin Logan dipoles. I called ML and got a pair of replacement tweeters. I removed the dead tweeter and installed a same exact replacement model from ML. Hooked up speaker and it sounded more extended and fuller and more detailed in the FR above 2500 crossover than the other. This was immediately obvious and was confirmed by playing mono tracks on Qobuz. So since I had ordered two, I changed out the other. Bam!!! Brand new speakers!  One cannot overstate enough the importance of the tweeter in the resultant sound quality one gets. The pair of speakers now sounds better and requires less EQ (I use high end pro balanced analog EQ for years). The best upgrade I’ve done so far. By far. And I never would have thought to do this were it not for that fateful day last week. Amazing!  Would have expected a rough edgy sound worse situation initially until broken in. But quite the opposite. 
so my questions are 1. Does a tweeter not need break in?  This is a “magnetically driven planar tweeter. The latter, which MartinLogan calls an ATF Transducer, measures 1.5" by 2.25" and consists of a lightweight film of polyethylene naphthalate film with an etched aluminum voice-coil, which is sandwiched between sets of neodymium-iron-boron magnets in a rigid steel housing.”

and 2.  Do tweeters degrade over the years, such that they lose both extension as well as resolution?  It’s astounding what a simple same model replacement has done. 
And finally, 3. Do we sometimes “upgrade” speakers when we could have accomplished the same thing simply installing new drivers at much less cost?

Thanks all for your thoughts!

tlcocks
tlcocks OP
471 posts
 

I also love the sound of this tweeter. It’s a wonderfully smooth and natural yet articulate high end. Great recordings cymbals sound amazing with this AMT

mulveling's avatar
mulveling
1,998 posts
 
  1. I’ve replaced the tweeter on just one side of Tannoy Kensington SE, years after their purchase. Almost certainly a different batch of manufacture, but same part number. No break-in required - the drop-in sounded perfect and continued to do so! Old tweeter still sounded great too; just developed a VERY slight resonant ringing noise (only noticeable one in a long while, on certain loud piano notes) that possibly could have been addressed by a careful cleaning. Wish I’d tried. Spares are hard to come by now, though Lockwood makes new replacements.
  2. Varies wildly by driver type & implementation. Planar magnetics are very different than other types. At issue there, I guess would be the coil’s "printing" on its VERY thin and delicate membrane material. Bad news if that starts to separate. Electrostats also have a very thin & delicate membrane, but without the complications of a printed "coil" - mainly, keep them away from dust or anything that could poke them. Many dynamic coil tweeters (the most common kind) could last decades or more with NO degradation (e.g. Tannoy "pepperpot" tweeters, like in the Kensington). Other dynamic coils (like Tannoy "tulip" DC’s) used ferrofluid in the gap, which can dry out (after say 20+ years?) - in that case, the old crusty fluid should be cleaned out and replaced with new fluid of a similar viscosity. Its performance can be degraded until this is done, but there’s no reason its lifetime has to be limited by this.

    The biggest risk to most tweeters is physical absue. 
corelli
1,019 posts
 

I had  a pair of speakers years ago with this type of tweeter.  I had buzzing issues which continued even after replacement of the pleated membrane.

I'm sure some of these sound great but agree these can be less robust than traditional designs.

tlcocks OP
471 posts
 

I am researching and it’s unclear to me if what ML calls an ATF transducer is actually an ATM, the latter of which requires not only a magnetic field but also a pleated diaphragm. I cannot see whether my tweeter has that pleated diaphragm. Help?  I see several of you have called my tweeter an ATM. Is it?

tlcocks OP
471 posts
 

Sorry mean AMT

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